Mariko, a demure office lady, reveals her dirty side by indulging in masturbation three times a week as per her strict rule. Apologizing with a shy "Sorry I'm so plain..." she meticulously stimulates her clitoris, repeatedly bringing herself to climax in a calm yet intensely focused manner. As her arousal builds, she earnestly attempts fellatio despite her inexperience, passionately sucking the cock before taking it into her naturally hairy, lewd pussy. The tight, pleasurable fuck quickly drives him wild, culminating in a powerful cumshot as she rides him in the cowgirl position. Smiling, Mariko rates the experience: "I'd give it 7.5 out of 10." She promises to work hard for a perfect score next time (sob).